LOS ANGELES (AP) - Southern California cornerback Josh Shaw has admitted to lying to school officials about how he sprained his ankles last weekend, retracting his story about jumping off a balcony to save his drowning nephew.

Shaw has been suspended indefinitely from all of the Trojans' team activities after acknowledging his heroic tale was "a complete fabrication," the school announced in a statement Wednesday.

The school didn't explain how Shaw actually was injured, but USC officials say they regret posting a story on their website Monday lauding Shaw's story about a second-story jump onto concrete to rescue his 7-year-old nephew.

"We are extremely disappointed in Josh," USC coach Steve Sarkisian said. "He let us all down. As I have said, nothing in his background led us to doubt him when he told us of his injuries, nor did anything after our initial vetting of his story."

Shaw is a fifth-year senior, a team captain and a key starter in USC's defensive secondary, widely regarded as a solid teammate and an important team leader for the 15th-ranked Trojans, who begin their first season under Sarkisian at the Coliseum on Saturday against Fresno State.

Shaw issued a short statement through an attorney on Wednesday after being suspended.

"On Saturday, August 23, 2014, I injured myself in a fall," Shaw said. "I made up a story about this fall that was untrue. I was wrong not to tell the truth. I apologize to USC for this action on my part. My USC coaches, the USC athletic department and especially Coach Sarkisian have all been supportive of me during my college career and for that, I am very grateful."

Within hours after Shaw's tale was made public, the football program received phone calls contradicting Shaw's version of his injuries. Sarkisian has not said who made the calls, but the school acknowledged the discrepancies Tuesday morning and began investigating Shaw, who initially stuck to his story.

"I appreciate that Josh has now admitted that he lied and has apologized," Sarkisian said. "Although this type of behavior is out of character for Josh, it is unacceptable. Honesty and integrity must be at the center of our program. I believe Josh will learn from this. I hope that he will not be defined by this incident, and that the Trojan Family will accept his apology and support him."

Shaw didn't attend practice Wednesday, missing his second straight day of workouts.

Sarkisian insisted the situation won't be a distraction for the Trojans, but still allowed only two of Shaw's defensive teammates to speak with the media after practice Wednesday morning.

Linebacker Hayes Pullard and defensive lineman Leonard Williams both acknowledged surprise at the situation that developed after Shaw's account was challenged, but remained supportive of their fifth-year senior captain.

"We were pretty shocked," said Williams, who hasn't spoken to Shaw. "Josh Shaw is a pretty loyal guy. I would never expect him to make up a story. I would never expect that out of him as a team leader."

Shaw's leadership and character were widely praised throughout his first two seasons of play at the school. He transferred back to his native Los Angeles area from Florida, in part to help out his ailing grandfather with the family landscaping business.

"Josh has been a great guy," Pullard said. "He has great character. I've never known him to lie about anything ... so it's surprising. This is exactly when our leadership roles come in. We talk to guys and let them know what's expected, and we'll keep us focused on our team."

Sarkisian hadn't even coached his first game at USC before the high-profile program presented another challenge for its fourth head coach in less than a year.

Sarkisian, a former USC baseball player and a longtime football assistant coach to Pete Carroll, knows all about the extra attention paid to the Trojans, who are in the final year of extensive NCAA sanctions for violations committed under Carroll, and he remains confident he can handle the latest round of extracurricular troubles.